Heavy Isotope Content Research Articles

Study of environmental isotope distribution in the Aswan High Dam Lake (Egypt) for estimation of evaporation of lake water and its recharge to adjacent groundwater

Oxygen-18 ((18)0) and deuterium isotopes were used to estimate the evaporation from the Aswan High Dam Lake and to investigate the inter-relation between the lake water and adjacent groundwater.According to stable isotopic analysis of samples taken in 1988 and 1989, the lake can be divided into two sections. In the first section extending between Abu Simbel and a point between EI-Alaki and Krosko, a remarkable vertical gradient of (18)0 and deuterium isotopic composition was observed. The second northern sector extending to the High Dam is characterised by a lower vertical isotopic gradient. In this sector in general, higher values of (18)O and deuterium contents were found at the top and lower values at the bottom. Also a strong horizontal increase of the heavy isotope content was observed. Thus, in the northern section evaporation is of dominating influence on the isotopic composition of the lake water.With the help of an evaporation pan experiment it was possible to calibrate the evaporative isotope enrichment in the lake and to facilitate a preliminary estimate of evaporative losses of lake water. The evaporation from the lake was estimated to be about 19% of the input water flow rate.The groundwater around the lake was investigated and samples from production wells and piezometers were subjected to isotopic analysis. The results indicate that recent recharge to the groundwater aquifer is limited to wells near to the lake and up to a maximum distance of about 10 km. The contribution of recent Nile water to the groundwater in these wells was estimated to range between 23 and 70%. Beyond this distance, palaeowater was observed with highly depleted deuterium and (18)0 contents, which was also confirmed by 14c dating. The age of palaeo groundwater in this area can reach values of more than 26,000 years.Recommendations are given for efficient water management of the lake water.

Comparison of Modeled and Observed Environmental Influences on the Stable Oxygen and Hydrogen Isotope Composition of Leaf Water in Phaseolus vulgaris L.

In this paper we describe how a model of stable isotope fractionation processes, originally developed by H. Craig and L. I. Gordon ([1965] in E Tongiorgi, ed, Proceedings of a Conference on Stable Isotopes in Oceanographic Studies and Paleotemperature, Spoleto, Italy, pp 9-130) for evaporation of water from the ocean, can be applied to leaf transpiration. The original model was modified to account for turbulent conditions in the leaf boundary layer. Experiments were conducted to test the factors influencing the stable isotopic composition of leaf water under controlled environment conditions. At steady state, the observed leaf water isotopic composition was enriched above that of stem water with the extent of the enrichment dependent on the leaf-air vapor pressure difference (VPD) and the isotopic composition of atmospheric water vapor (AWV). The higher the VPD, the larger was the observed heavy isotope content of leaf water. At a constant VPD, leaf water was relatively depleted in heavy isotopes when exposed to AWV with a low heavy isotope composition, and leaf water was relatively enriched in heavy isotopes when exposed to AWV with a large heavy isotope composition. However, the observed heavy isotope composition of leaf water was always less than that predicted by the model. The extent of the discrepancy between the modeled and observed leaf water isotopic composition was a strong linear function of the leaf transpiration rate.

Exemple d'etude geochimique et isotopique de circulations aquiferes en terrain volcanique sous climat semi-aride (Amurga, Gran Canaria, Iles Canaries)

A hydrochemical and isotopic study of a groundwater flow system in volcanic media has been carried out in the southern part of Gran Canaria (Canary Islands). Monthly samples of precipitation were collected over a two year period at stations distributed all over the island. Sampling of groundwaters took place mainly from drillholes in the Amurga phonolitic massif but also from wells and springs discharging from the volcanic and related detrital formations. The δ 2H vs. δ 18O relationship of the precipitation is close to the “global meteoric water line”. Two distinct altitudinal isotopic gradients are observed. On the warm and dry southern slope, the combination of a contribution of saharan dusts and seasprays and of partial evaporation explains the high content of dissolved salts (Cl −, SO 2− 4) in precipitation. Additional processes may be invoked as sources of groundwater mineralization: leaching of silicate minerals during infiltration and/or from hydrolysis during the long residence time of the waters in the volcanic rocks. Salt content is increased through a concentration of the percolating solutions by evaporation, as shown by their stable isotope contents ( 18O, 2H). The groundwaters in the phonolitic aquifer are well differentiated from the deeper groundwaters, which are recharged at an altitude of about 1000m above sea level, or even less, if exceptional episodes of rain have a lower heavy isotope content. The interpretation of the 13C contents of soil CO 2, sampled throughout the area, and of the 13C and 14C contents of total dissolved inorganic carbon (TDIC) leads to the concept of an incorporation of pure biogenic carbon under open-system conditions in the Amurga waters. For these groundwaters, high estimates of residence time (ca. 11000 years) can be calculated from the low 14C activities. In the neighbouring valleys, the input of deep “dead” volcanic carbon and the occurrence of mixing do not allow an exact quantification of residence time values. However, they seem to be shorter than those measured for the Amurga waters.

Deuterium and Oxygen-18 in Surface Waters of GDR draining to the Baltic Sea

A general view is presented of deuterium and 18O measurements of water samples collected at running and standing surface waters in German Democratic Republic. The values confirm earlier observations that the surface waters are influenced by evaporation with respect to the isotopic composition of groundwater. Nevertheless, stronger evaporation effects are restricted to larger lakes. The amount of surface water discharge from GDR to the Baltic Sea and the δD and δ18O values are discussed. The river Oder provides about 90% of the whole surface run-off. The other watercourses to the coast are unimportand. The mean heavy isotope content of surface run-off was calculated to be −8.3‰ for δ18O and −61‰ for δD (vs. SMOW), respectively.

Deuterium and oxygen-18 in the baltic sea

Results are presented of deuterium and 18O measurements of water samples collected at 15 stations covering the southern and central part of the Baltic Sea. In general, they confirm earlier findings with respect to vertical stratification of the heavy isotopes in the Baltic and their relation to salinity. The heavy-isotope content of the zero-salinity component of the Baltic Sea (freshwater inflow and precipitation) was estimated to be −8.9‰ for 18O and −68.1‰ for D, respectively. It appeared that the isotopic composition of this component is already slightly modified by evaporation and isotope exchange with atmospheric moisture.

Evolution de la composition isotopique de l'eau ( 18O) dans le continuum sol-plante-atmosphere : Exemple d'une parcelle cultivee en ble versailles, France, Juin 1984

Simultaneous measurements of 18O in samples of soil, plant water and atmospheric water vapor at the experimental site of La Miniere (Versailles, France) reveal: - strong spatial and temporal variations of the heavy isotope content of water in the continuum soil-plant-atmosphere; - isotopic free water evaporation model under constant level simulates fairly well the transpiration of leaves: dominant factors are in this case relative humidity of the air and kinetic enrichment factor; - transpiration under steady-state conditions provides water vapor whose the isotopic composition is those of collar water in the plant. This vapor is clearly showed by the isotopic method.

Stable isotope dilution assay for branched chain alpha-hydroxy-and alpha-ketoacids: serum concentrations for normal children.

A stable isotope dilution assay is described for the six branched chain alpha-hydroxyacids and alpha-ketoacids that accumulate in serum in maple syrup urine disease. The method employs sodium borodeuteride reduction of the alpha-ketoacids in situ to once-labeled hydroxyacids, addition of a more extensively labeled analog as internal standard, isolation of the organic acids by ether extraction, and quantitation by gas chromatography/mass spectrometry in selected ion monitoring mode. A set of three areas are obtained for each of the three branched chain hydroxyacid peaks, and these are corrected for natural abundance heavy isotope content and for isotopic impurities in the labeled standards and precursors. The corrected areas are then converted to concentrations of the endogenous three hydroxyacids and the original three ketoacids in serum.

Temperature and rainfall variation in the holocene based on comparative palaeoecology and isotope geology of a hummock and a hollow (Bourtangerveen, The Netherlands)

The present study combines palaeoecological and isotope-geological analyses of Holocene peat sequences to yield detailed information on temperature and rainfall. Analyses were carried out on two peat sections from the Meerstalblok (NE of the Netherlands). The Meerstalblok is one of the last remnants of the formerly extensive Bourtangerveen, situated between the Hondsrug (west) and the river Ems (east). A map of the stratigraphy of the peat profile shows that this part of the bog was differentiated into a hummock and a hollow during almost the entire period of peat accumulation, and that levels of the same age are situated lower in the hollow than in the hummock. The palaeoecological part of the study consists of a micro- and a macrofossil analysis. From the microfossil (pollen) analysis the development of the surrounding forests was reconstructed. Pollen concentrations and the relation between 14C dates and cumulative pollen concentrations were used to derive a time-scale according to the method of pollen density dating. Because the fine-scale accumulation of peat fluctuates strongly, this time-scale is thought to be more accurate than interpolation through depth between the dates. Macro- and microfossil analyses together provided a detailed picture of vegetation development of the raised bog in the period between 7000 and 1000 B.P. The bog development showed alternating wet and dry phases, probably as a response of the raised bog to differences in the available amount of effective rainfall. A semi-quantitative curve for the moisture conditions of the bog was calculated from the palaeoecological data obtained. Several phases corresponded to similar ones of a neighbouring raised bog (the Engbertsdijksveen). In the case of wetter vegetation types, the average seepage of the bog increases and more water may be discharged, whereas in the case of drier vegetation types the average seepage decreases and more water may be stored. The ratio between the area and the boundary of the southern part of the Bourtangerveen limits the total discharge of effective precipitation in this part of the bog. In case the effective rainfall increased to a quantity above the upper limit, a better natural drainage should develop. This probably occured at 2500 B.P. when a bog-burst discharged a water surplus and eroded the bed of the bog rivulet Runde. The effect of this bog-burst seems to be reflected in the hollow sequence of the Meerstalblok. Comparison of the regional pollen curves from the hummock and the hollow revealed an erosion hiatus of roughly 400 yrs and the disturbance of the adjacent layers in the hollow sequence. The local development confirmed the disturbance in the form of charcoal and seeds of Drosera intermedia. After the bog-burst probably a new balance was established in equilibrium with an increased amount of precipitation. The isotope-geological part of the study consists of measurements of the 2H/ 1H ratio in cellulose derived from peat. The ratio of precipitation depends on the temperature difference between the region of evaporation and the region where the rain falls. Because during a climatic change the temperature differences at higher latitudes are greater than at lower latitudes, the 2H/ 1H ratio of precipitation is related to the temperature. However, the 2H/ 1H ratio of cellulose of bog plants is also taxon-dependent. Transpiration of water from leaves enriches the heavy isotope content in the plant. This transpiration together with a biochemical fractionation of isotopes during photosynthesis introduce the species-bound dependence of the 2H/ 1H ratio. By determining the relative species abundance of each sample, the 2H/ 1H ratio was corrected for its taxon-dependence and a temperature record could be derived. Periodic regression analysis showed that a period of 200 yrs is the dominant one in this temperature curve. These analyses were carried out in the two Meerstalblok sections and in one from the Engbertsdijksveen. The results of the three sequences were mutually compared and also compared with stable isotope data ( 18O/ 16O) from the Camp Century ice core from Greenland. It is concluded that the average annual temperature dropped from over 10° to about 9°C between 4000 and 3000 B.P., rose shortly after 3000 B.P. to almost 11°C and fell off again to about 9°C shortly after 2000 B.P.

Oxygen and hydrogen isotopic ratios in groundwaters and river waters from India

A comprehensive set of measurements of oxygen and hydrogen isotopic ratios in groundwaters as well as waters from rivers, lakes, hot springs etc. taken from a variety of locations in India has been carried out for the first time. Isotopically the most depleted samples occur in the high altitude precipitations in the Himalayas e.g. in the lakes of Bhutan and the source water of the Ganga. The shallow groundwater data display a continental effect where the heavy isotope content decreases with distance from the coast (about 4 to 6 per mil decrease in δ18O per 1000 km). The δ D and δ18O of these fresh waters are linearly related and an analysis of this relation vis-a-vis the meteoric water line shows the unambiguous effect of enrichment due to evaporation from soils.

Deuterium and oxygen-18 in European groundwaters — Links to atmospheric circulation in the past

A thorough discussion of deuterium and 18O isotope ratios found in modern infiltration waters and in old groundwaters recharged during the final stages of the last glaciation in Western and Central Europe is presented. Old European groundwaters are depleted in deuterium by ∼ 12%. when compared to modern infiltration waters. The continental gradient in deuterium content found in these waters is very similar to that presently observed in infiltration waters and in precipitation. This fact strongly suggests a constant circulation regime of the atmosphere over Europe for the past 35,000 yr. Relative constancy of atmospheric circulation during that time makes a quantitative interpretation of the depletion in heavy-isotope content of glacial waters meaningful in terms of changes in surface air temperature over Europe at the transition from the last ice age to the Holocene climate. The shift in air temperature deduced from the above-mentioned depletion in deuterium content reaches ∼ 7°C. This value is in good agreement with previous estimates based on simulation of the ice age atmosphere and on measurements of noble-gas contents in European groundwaters. The relation between δ D- and δ 18O-values found in old European groundwaters is essentially identical with the well-known relationship δ D = 8δ 18O + 10, which is proved to be valid for modern precipitation and infiltration waters. It means further that deuterium excess in European meteoric waters, defined as d = δ D − 8δ 18 O did not undergo substantial changes for at least 35,000 yr. This fact provides a strong argument in favour of the hypothesis that the increase in relative humidity by ∼ 1090 over the glacial ocean, which is a widely accepted opinion nowadays, was probably not a world-wide phenomenon.

The content of heavy oxygen isotope in the water masses of the Philippine Trench

The H 2O 18 content of a group of 11 water samples from 7558 to 9864 m depth was compared with that of another group of 4 samples from 3830 to 4202 m depth. The difference was 0·1 ± 0·2 p.p.m., i.e. not significant. Approx. 100 p.p.m. should be expected in case of equilibrium.

Heavy Water and Metabolism

Previous articleNext article No AccessHeavy Water and MetabolismDenis L. FoxDenis L. Fox Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Quarterly Review of Biology Volume 9, Number 3Sep., 1934 Published in association with Stony Brook University Article DOIhttps://doi.org/10.1086/394466 Views: 4Total views on this site Citations: 5Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:Agnieszka Fulczyk, Eliza Łata, Ewa Talik, Milos Dolnik, Teresa Kowalska, Mieczysław Sajewicz Impact of D2O on the peptidization of L-alanine, Reaction Kinetics, Mechanisms and Catalysis 79 (May 2020).https://doi.org/10.1007/s11144-020-01783-yEivydas Andriukonis, Elena Gorokhova Kinetic 15N-isotope effects on algal growth, Scientific Reports 7, no.11 (Mar 2017).https://doi.org/10.1038/srep44181Xiyan Li, Michael P Snyder Yeast longevity promoted by reversing aging-associated decline in heavy isotope content, npj Aging and Mechanisms of Disease 2, no.11 (Feb 2016).https://doi.org/10.1038/npjamd.2016.4S. C. Brooks The permeability of erythrocytes to deuterium oxide (heavy water), Journal of Cellular and Comparative Physiology 7, no.22 (Dec 1935): 163–171.https://doi.org/10.1002/jcp.1030070203Denis L. Fox Concerning enzymic reactions in heavy water, Journal of Cellular and Comparative Physiology 6, no.33 (Aug 1935): 405–424.https://doi.org/10.1002/jcp.1030060307